Grinding machine for finishing borings



Aug. 12, 1930. K. JlUNG GRINDING mcrmm FOR FINISHING sonmas 2 Shuts-Shoot 1 Java/2301* fiat? 72029 Filed March 26 1929 Aug. 12, 1930. K. JUNG 1,172,121

GRINDING MACHINE FOR FINISHING BORINGS Filed March 26, 1929 2 Sheets-Sheet 2 Patented Aug. 12, 1930 PATENT OFFICE KARI; JUNG, OF BERLIN, GERMANY GRINDING MACHINE ron rmrsnme :BoRINGs Application filed March 26, 1929, Serial No; 349,971, and in Germany March 28, 1928.

In the process of finishing borings b internal grinding'machin'es frequent chec s of measurements during such grindlng are necessary in order to obtain the size of the bore 6 as true as possible. In the case of precision" work, it is usual to finish up by a special process, the last few thousand parts of a millimeter by means of a reamer of a special design or the like. This work comparatively entails time and ,in particular the finishing by means of the special r-eamer which must be done by hand 'is a real time waster.

The present invention purports to accomplish the entire grinding operation to true size without the necessity of resetting in the machine and without recourse to hand labour. The work can thus be finished in only one'setting. To this end the work isground by the usual grinding tool to an easy approximation of say .05 to .01 of a millimeter whereupon it is finished oif to true size without being reset by the aid of an adjusting tool.

The drawing shows by way of example one form of execution of the invention, namely Fig. 1 isa front View of a machine working in accordance with the present invention partly in section,

Fig. 2 is a side view of Fig. 1 and 0 r Fig. 3 is a part of Fig. 1 in a larger scale.

In the drawing is shown as a a stand with a hollow bored spindle b on bearings a. This spindle carries the clamps 0 which hold the work d by any one of the known methods. This latter in the case of this example consists of a ring the internal bore of which it is desired shall be finished by grinding. Opposite to the 'workholder is shown on a tool holder e a grinding disc f, the diameter of which is smaller than the bore of the work wheel 0 is arranged on a shaft 0 bearing on its other end a worm 0 meshing with a worm-wheel 0 This worm-wheel is mounted on a shaft o on the other end of which a gear wheel 0 is arranged meshing with a rack 0 fastened on the slide 11.. The movement of the tool holder e in its longitudinal direction is effected by means of the guide 0 Within the main frame A a pulley Bis journalled. This, pulley is driven by any suitable means. Arranged on the same axis withv said pulley are two other pulleys C and C the former of which serving for driving the pulley p by means of a belt p The pulley p is arranged on the same spindle with another pulley p adapted to drive by means of a belt 39 the pulley e on the shaft of the tool holder 6.

The pulley 0 drives by means of the belt "9 a pulley 9 arranged on a shaft 9 This latter shaft has arranged on it a further pulley not shown in the drawing and adapted to rotate by'means of the belt 9 the pulley g on the spindle b. 1

The stand a is fixed on the main frame A.

Within the hollowbored spindle b there is a rodh for instance guided by rings i'carrying at its foremost extremity an adjustable tool is. This adjustable tool is preferably also a grinding tool but does not revolve. But this tool 1 6111121 be introduced into the boring of the wor d for the purpose of grinding by means of a pin or rod h in the direction of the spindle through a corresponding bore m of the clamps. The movement is carried out by means of a hand lever n, pivoting about a bolt 7?) and journalled in an arm n fastened on or being integral with the stand A.

The bore of the work piece d is ground firstly in the usual way by the grinding disk 7, the grinding disk being introduced into the said bore and then set in a radial direction by means of the hand-wheel 0 until the approximate size of the bore has been reached.

A verification as to the correct measurement is not done nor is the grinding disc again in serted for purposes of ascertaining the true size but according to the invention the process of internal grinding is topped as soon as the size of the bore has reached an accuracy of approximately .01 millimeter. After such accuracy having been reached the grinding disc f is removed from the work piece and the finishing operation is made by means of the adjustable tool 7:.

The outer diameter of tool must conform precisely to the diameter of the bore that is to be ground. The adjustable tool it thus corresponds in its action to that of a reamer with the difference of possessing no teeth yet being so arranged'on its surface as to be able to grip the hardenedmaterial of the work. It may for instance have the shape of an emery spindle or it may consist entirely of a grinding material. The tool is preferably made adjustable with respect to its diameter so as to enable it being immediately corrected when ait'ected by wear and tear or else to enable its adoption to borings of various diameters. Adjustments may be effected in similar manner as this is done With adjustable reamers or other tools diametrically adjustable.

It is not altogether necessary that the-adjustable tool shall slide along the hollow bored spindle which is carrying the work, but it may be fed to the tool in a different way, say from the front whereby the grinding'wheel and adjusting tool rest for instance 0111 a slide rest or on a revolving head or the li re.

By preference however the grinding tool or the adjustable tool shall not revolve, yet if it is desired they may do so at a suitable speed in the same direction with the work, but with a different velocitv to this or they may revolve in the opposite direction.

I claim 1. An internal grinding machine for grinding borings comprising in combination with the rotatabl" spindle of the work piece, a grinding tool adapted to be fed in the usual manner in a radial direction "and an adj ustable grinding tool adapted to be fed in its axial direction and having an outer diameter corresponding exactly to the desired final size of the boring.

2. An internal grinding machine for grinding borings comprising, a hollow-bored spindle adapted to take the work piece, an adjustable grinding tool inserted in the said spindle and adapted. to be fed in an axial direction, the diameter of which corresponding exactly to the desired iinal size of the boring and a second grinding tool adapted to be fed in the usual manner in a radial direction.

3. An internal grinding machine for grinding borings comprising in combination with the rotatable spindle of the work piece, a grinding tool adapted to be fed in the usual manner in a radial direction'and an adjustable grinding tool adapted to be fed in its axial direction and having an outer diameter corresponding exactly to the desired final size of the boring, said adjustable (grinding device being adjustable as to its iameter.

4. An internal grinding machine for grinding borings comprising in combination with the rotatable spindle of the Work piece, a grinding tool adapted to be fed in the usual manner in a radial direction, means for feeding said grinding tool and an adjustable grinding tool adapted to be fed in its axial direction and having an outer diameter corresponding exactly to the desired final size of the boring.

5. An internal grinding machine fox grinding borings comprising in combination with the rotatable spindle oi the work piece, a grinding tool adapted to be fed in the usual manner in a radial direction, means for feeding said grinding tool, an adjustable grinding tool adapted to be fed in its axial direction and having an outer diameter corresponding exactly to the desired final size of the boring and means adapted to feed said adjustable grinding tool in its axial direction.

In testimony whereof I afiix my signature.

KARL JUN G. 

